This invention relates to the art of processing information from optical image sensors, and more particularly to a new and improved circuit and method for converting signals from a photoelectric image sensor into digital signals containing information as to a characteristic of the sensor signals.
One area of use of the present invention is with solid state image sensors of the photoelectric type for providing output signals having a characteristic determined by the manner in which light is incident thereon. Such sensors include an arrangement of photoelectric elements along a line or in a pattern or array which elements periodically are electrically sampled or scanned to provide a series of output signals or pulses. The amplitudes of these pulses contain information as to the amount and location of light incident on the sensor. For converting this analog information to digital form for information processing, integration techniques have been employed which involve determining the area under a curve defined by a series of such pulses.
However, situations can arise where it would be useful to have information as to the absolute value or amplitude or each pulse. This would allow pulse-to-pulse amplitude comparisons, for example, and provide rate of change information. Accordingly, it would be highly desirable to provide a signal processing circuit enabling such information to be obtained from photoelectric image sensors of this general type.